Modern warfare has developed new threats and new uses for old weapons. Deployments place units in areas exposed to a variety of weapons fired at close range and with little warning. Countermeasures must be developed and deployed to neutralize such threats.
For example, various rocket-propelled grenades (RPGs) are widely used against armored and unarmored targets. RPGs are typically fired within a few hundred meters of a target, and often from doorways and behind walls, providing little reaction time. Urban environments are particularly suited to RPG attacks.
Countermeasures may be available against many types of projectiles. Under many conditions, however, the countermeasures must be deployed extremely quickly, limiting the effectiveness of many countermeasures. In addition, some countermeasures, such as extra armor, may not be suited to particular units.